RED DEER, Alta. - A trial for two men charged in the deaths of a central Alberta couple and their daughter has heard about charred remains discovered inside the family's farm home and a dead pet dog found nearby.

Two members of the Castor Fire Department were the first witnesses to testify at the first-degree murder trial for Jason Klaus and Joshua Frank.

They face three counts each of first-degree murder in the deaths of Klaus's parents, Gordon and Sandra Klaus, and their daughter Monica Klaus.

Lee Bagshaw, the fire department's deputy chief, testified on Wednesday that the house near Castor was engulfed in flames when crews arrived on Dec. 8, 2013.

Bagshaw said firefighters set about protecting nearby buildings and a propane tank next to the house, but he soon noticed a dead chocolate-coloured Labrador retriever nearby.

Bagshaw told the judge-alone trial in Red Deer that the scene started to look suspicious when he spotted a fuel can — about two-thirds full — sitting about two metres from the home's door.

During cross-examination, defence lawyer Allan Fay asked Bagshaw if the nozzle was out, as if ready to pour, or if it was tucked away. Bagshaw said he noted it was tucked away.

Travis Ryan, another fire department member, testified he came across what appeared to be charred remains inside the home.

He said the home's residents were nowhere to be seen, which also led firefighters to think something wasn’t right.

Earlier Wednesday, the final video recordings of Frank's interviews with police in August 2014 were played in court as part of a voir dire to determine the admissibility of the accused man's statements to police as evidence.

Frank told investigators that in the month following the deaths, Klaus paid him between $3,500 and $4,000, which was dispensed in $500 cash instalments.

Frank said the money was in exchange for carrying out the murders and for keeping his mouth shut about it.

The trial has previously heard that Frank told police he was blackmailed and threatened into killing the family by the couple's son.

He said Klaus was with him stride for stride when they entered the house and that he was told to shoot all three or he would be killed.

He also said in the interview that after the shooting he got a can of aviator fuel from a nearby Quonset hut and Klaus used a butane barbecue lighter to set the house ablaze and shot the dog before they both fled.

Frank also revealed to investigators that he had had a sexual encounter with Klaus when he was 14. He told police about the co-accused demanding Frank perform sexual acts.

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